Is too much screen time bad for kids?

You check in to say good night to your son only to find he is playing "Fortnite" in bed.

Or your daughter is busy texting when she is supposed to be studying.

Children
and their phones are inseparable today, and all that reading and
playing games on their handheld devices may be harming their vision.

To
reduce screen time, some parents ban phones at the dinner table. This
applies to both adults and children. And in some homes, playing games or
texting must stop two hours before bedtime.

To put a hard stop on
screen time, some moms and dads set time limits on their children's
daily device use. For example, when a total of two hours of screen time
has been reached, no more texting, game playing or YouTube watching.

Definition of "screen time"

"Screen
time" refers to the amount of time a person spends staring at the
digital displays of computers, tablets (iPads, for example) and
smartphones.

According to The Vision Council, 72 percent of
American parents report their children routinely engage in more than two
hours of screen time per day. And it's very likely most kids actually
spend significantly more time staring at screens than their parents
think they do.

As kids grow, their screen time tends to grow with
them. And even very young children these days are spending a significant
amount of time each day staring at screens. According to Common Sense
Media, young children in the U.S. spend the following amount of time
each day using digital devices:

Kids under 2 years of age: 42 minutes per day

Kids ages 2 to 4: 2.5 hours per day

Children ages 5 to 8: nearly 3 hours per day

Why might too much screen time be a problem for kids?

The
Vision Council says 30 percent of parents report their children
experience at least one of the following symptoms after being exposed to
more than two hours of screen time per day:

Headaches

Neck/shoulder pain

Eye strain, dry or irritated eyes

Reduced attention span

Poor behavior

Irritability

Any of these symptoms could potentially affect academic performance and social interactions.

The rapid rise of myopia,
or nearsightedness, worldwide has been linked to increased use of and
exposure to electronic devices. In Singapore, for example, 65 percent of
students in Primary 6 are myopic. In the United States and Europe,
where myopia rates traditionally have been lower, around half of young
adults now suffer from myopia compared with 25 percent in the 1970s.

Why blue light can be bad for you

The
LED screens of computers and portable digital devices emit a broad
spectrum of visible light. Most of these light rays are harmless, but a
portion of the light emitted by these screens is relatively high-energy
visible light called "blue light."

Blue
light has shorter wavelengths and higher energy than other visible
light rays. And laboratory research suggests certain bands of blue light
may be harmful to the light-sensitive retina of the eye over time.

Blue
light also plays an important role in regulating our body's circadian
rhythm. This basically is an internal clock that's running in our brain
and cycles between alertness and sleepiness at regular intervals over a
24-hour period. It's also called our sleep/wake cycle.

Too much
exposure to blue light at the wrong time of day can disrupt a person's
normal sleep/wake cycle, which can have serious health consequences.

Risks of too much screen time for kids

When
talking about the risks of too much screen time for kids, we’re
basically talking about the potential harmful effects of too much blue
light.

And while it's true that staring at the screens of digital
devices adds to the amount of blue light exposure kids get over the
course of their lifetime, it's important to point out that the sun emits
far more harmful blue light than computers, e-tablets and smartphones.
So the blue light exposure from digital devices is an added exposure, over and above the larger amount of blue light exposure a person gets from sunlight.

A second important factor to consider is the timing
of the exposure. Blue light exposure from the sun only occurs from
sunup to sundown. But blue light exposure from screen time can occur at
any hour of the day, including well into the night.

Possible risks from too much screen time for kids can be categorized as immediate or long-term.

Immediate risks

Immediate
risks from too much screen time generally occur relatively soon after
repeated blue light exposure. Many of these risks are associated with
circadian rhythm disruption caused by staring at digital screens well
into the night, which can make it much harder to fall asleep at a normal
time.

Sleep disruption can be especially problematic for
children, leading to daytime drowsiness and poor performance in school
because of it. Disruption of the sleep/wake cycle also can eventually
lead to weight gain and obesity-related health problems.

Research
has shown that people who experience disrupted 24-hour cycles of sleep
and activity also are more likely to have mood disorders, lower levels
of happiness and greater feelings of loneliness.

Also, an
intriguing two-year study of more than 2,500 normal Los Angeles high
school students found that teens who reported greater digital device use
and screen time during the study were about 10 percent more likely to
develop ADHD symptoms by the end of the study period. (The researchers
pointed out, however, that this doesn't prove a direct cause-and-effect
relationship and more research is needed to fully understand the
association between screen time and ADHD symptoms.)

Long-term risks

Wearing glasses that filter blue light from digital screens may help reduce your child's risk of eye problems later in life.

The
simple truth is that the long-term risks of incremental blue light
exposure from frequent use of digital devices is not yet known. This is
because no previous generation has been exposed to comparable levels
blue light from digital devices from childhood on.

It will
probably take several decades before the long-term effects of extensive
screen time for kids are better understood. But there is already some
related research that suggests it may be wise to limit blue light
exposure starting at an early age.

For example, researchers in
Japan and Switzerland investigated what happened to the retinas of aging
eyes from blue light exposure after cataract surgery.
In the study, 79 eyes received a clear intraocular lens (IOL) that did
not block blue light, and 52 eyes received a yellow IOL that blocked
blue light. (Prior to cataract surgery, the retinas of all eyes were
protected from blue light by the eye's natural lens that had become
clouded by cataracts.)

Two
years after cataract surgery, none of the eyes that received the yellow
IOL that blocked blue light showed any new or worsening signs of macular degeneration
(AMD). However, among eyes that received the clear IOL that didn't
block any blue light, 15 percent of these eyes showed new or worsening
signs of AMD.

The results of this study suggest that the retinas
of aging eyes are more susceptible to oxidative damage caused by blue
light exposure. If this is true, then it may be prudent and wise to take
steps to reduce premature aging of the retina by limiting the amount of
blue light exposure the eye receives throughout life.

The
greatest benefit may occur when these protective measures are taken
during childhood, because this is when the media of the eye (the lens in
particular) are exceptionally clear and allow the greatest amount of
blue light to reach the retina.

How to cut back on screen time

So then, what can a parent do to prevent harm to their child's eyes (and overall health) from too much screen time?

It's
unlikely kids will reduce their use of digital devices. So the answer
lies in taking steps to limit the amount of blue light reaching their
eyes while they are using these devices.

Eyeglasses and sunglasses to reduce blue light

The sun emits much more blue light than digital devices. All kids should wear sunglasses outdoors to reduce their lifetime exposure to harmful blue light.

One
solution is to purchase eyeglasses with lenses that reduce the amount
of blue light that enters the eyes from computer, e-tablet and
smartphone screens. A number of lens manufacturers produce eyeglass
lenses that filter blue light.

A third option is to purchase glasses with photochromic lenses.
These sun-sensitive lenses block some blue light indoors and have the
added advantage of automatically blocking additional blue light from the
sun outdoors without the need for a separate pair of prescription
sunglasses.

Yet another option — and the best option for superior protection from harmful blue light from the sun — is a pair of polarized sunglasses for outdoor wear.

Blue light filters to reduce exposure

But
what if your child doesn't need prescription glasses? The most
convenient option in this case is to purchase a protective blue light
filter that can be applied to the surface of your child's digital
devices. Examples include InvisibleShield Glass+ VisionGuard screen
protectors from ZAGG.

Also, remember to use the blue light
filtering features on certain devices (like Apple's Night Shift), or
multi-platform apps that block blue light, such as f.lux and Iris.

Set limits on screen time

To
reduce the risk of your child disrupting his or her sleep/wake cycle,
create a "no-screens" rule at least an hour or two before their
scheduled bedtime.

Or set a time limit on your child's phone use.
Apple, Google and other tech companies have recently introduced time
management features and apps that allow you to monitor your child's
daily screen time. Visit your phone vendor's website or store to learn
more.

Be proactive as a parent. One goal maybe? Spend more quality
time together and less screen time with your son or daughter left to
their own devices. Better yet? Protect your child's vision while they're
watching YouTube videos, posting Snaps and playing games.

Does not know how to parse this hyperlinkThe 2017 Common Sense Census. Common Sense Media. Accessed December 2018.

How to use Apple's new screen time and app limits features in iOS 12. The Verge. September 2018.

Digital eye strain. Does not know how to parse this hyperlink. Accessed July 2018.

Association of digital media use with subsequent symptoms of attention-deficit/hyperactivity disorder among adolescents. JAMA. July 2018.

Association of disrupted circadian rhythmicity with mood disorders, subjective well-being, and cognitive function: a cross-sectional study of 91,105 participants from the UK Biobank. The Lancet
Psychiatry. June 2018.

Google rolls out app time management controls. TechCrunch. May 2018.

Circadian rhythms in diet-induced obesity. Advances in Experimental Medicine and Biology. September 2017.